JACKSONVILLE, Fla. -

Duval County is the only school district to increase the number of A schools and decrease the number of F schools, according to the 2012 school grades report for elementary, middle and some combination schools released Wednesday by the Florida Department of Education.

Meanwhile, the number of highly-rated schools in Florida dropped sharply this year. The report showed a 24 percent drop in the number of A-rated schools, and the number of schools that received D and F grades increased.

"A decrease in school grades was expected because of the increased rigor," said Duval County Superintendent Ed Pratt-Dannals. "While we have seen some reductions, they are not as drastic as we anticipated. I commend our teachers and principals for their hard work in preparing our students for the most rigorous expectations in the country."

This year in Duval County, 115 schools out of the 142 schools earned excellent, good or satisfactory grades, while four schools received a D or F. All of Duval's 21 high schools are still awaiting their grades, which incorporate access to and performance in accelerated course work, college readiness and graduation rates. High school scores are scheduled to be released in December.

Highlands Elementary School improved from an F to a B, and Cedar Hills Elementary also rose three letter grades from a D to an A.

Northshore Elementary received a B, up two letter grades from a D last year. The school was once an F school.

"I was kind of upset that everyone said we wasn't going to make it," said fourth-grader Kristopher Payne. "So I would like to say to all of them, we made it."

Eighteen schools went up one letter grade, 10 schools went up two letter grades, and 59 schools maintained their grades.

Among Duval schools, 49 received an A -- up from 48 last year -- 29 a B, 37 a C, 23 a D and four an F -- down from five last year. Eighty percent of Duval schools made excellent, good or satisfactory grades.

"I think we have done better," Pratt-Dannals said. "We're not completely there. We've done better at analyzing where each individual student is in terms of progress toward expectations and put in place more individual helps for those students."

In Clay, 21 schools received an A, 10 a B and one a D. Four schools improved, while 10 schools decreased.

In Nassau, six schools received an A and two a B.

In St. Johns, 17 schools received an A, eight a B and one a C.

State school officials said as Florida continues efforts to raise school performance, the state's school grades are being calculated using more rigorous standards and new achievement levels.

According to the report, 89 percent of schools (2,301) in Florida earned an A, B or C grade and 11 percent (285) earned a D or F grade.

"This has been a year of tremendous change for Florida's students, teachers and schools," said Commissioner of Education Gerard Robinson. "Florida's economic future depends on preparing our students for success. The high standards we have in place today will help our students prepare for college, the workforce and life. I am confident that we are on the right path to prepare our students to compete with the best in the nation and around the world."

Florida has raised expectations for school grades five times in the last 10 years. The results show that after an initial drop, school grades improved consistently in the years that followed.

As Florida moves toward implementing the Common Core State Standards in 2014-15, the progress seen over the next few years will smooth the transition to the more challenging standards, school officials said.

"I am particularly pleased that it is the first time that we have included students who are just learning English and students with disabilities in the school grade performance component," Robinson said. "It is important that we measure our schools by the performance of all students, since that is the most accurate and fair way to represent our diverse state."

Based on a recommendation by the Commissioner's Taskforce on Inclusion and Accountability, the state Board of Education approved a policy ensuring that no school would drop more than one letter grade from the previous year. This provides Florida's public school leaders, teachers and students a year of transition to the new standards.